NASA concept for a lunar nuclear reactor
A NASA concept for a lunar fission power system. NASA is funding three teams to study reactor designs but the future of the program is uncertain. Credit: NASA

CLEVELAND — Advocates of nuclear power systems for lunar exploration are calling on NASA to find ways to continue development amid fiscal challenges and competing priorities.

NASA selected three teams in June 2022 for phase 1 studies of fission surface power systems, small nuclear reactors intended to support later phases of the Artemis lunar exploration campaign. The teams, led by Lockheed Martin, Westinghouse and IX, a joint venture of Intuitive Machines and X-Energy, received $5 million each for initial design studies.

The focus of those efforts is to design a 40-kilowatt reactor that weighs no more than six metric tons and can operate for 10 years, said Lindsay Kaldon, Fission Surface Power (FSP) program manager at NASA’s Glenn Research Center, during a panel at the American Astronautical Society’s Glenn Memorial Symposium July 18. NASA also requires the use of high-assay low-enriched uranium, or HALEU, to address nuclear non-proliferation concerns.

NASA and the Department of Energy (DOE), which partnered with NASA on the project, levied few other requirements on the companies. “We are able to get really innovative ideas from the three partnerships,” she said. “We’re able to see some out-of-the-box thinking.”

The FSP program plans a second phase to turn one of the designs into flight-certified hardware. NASA has not set a date for releasing a request for proposals for that second phase. NASA is also working on its own government reference design in cooperation with DOE.

The uncertainty about the schedule for the next phase of FSP has some in industry concerned. “We’ve got a lot of momentum right now in nuclear space,” said Vince Bilardo, an industry consultant supporting the IX team, citing not just the FSP work but various initiatives to develop nuclear thermal propulsion and nuclear electric propulsion.

However, he said he was worried that “political realities” such as a divided Congress would make it difficult for NASA to move ahead with the next phase of FSP. “So, you’ve got at least two fiscal years of authorizations and appropriations in front of us here,” he said, “where it’s going to be potentially very difficult for NASA to secure a program new start for phase two of Fission Surface Power.” He estimated that phase of the program could cost a billion dollars over four to eight years.

That program also has to compete with all of the other elements of Artemis for funding. “In that current environment, my take on that is it’s going to be a challenge for NASA to secure formal new start project authorizations for these different Artemis elements,” he said.

He urged NASA to find ways to extend the phase one contracts to minimize any gaps between that work and the phase two competition. Doing so, he said, would avoid “a gap in coverage that causes us on the industry side to have to reassign our teams.”

The agency should fund work on enabling technologies for fission power systems, Bilardo argued, which can be done in parallel to design studies because those technologies will be used in almost any design. “We know what these systems need to look like, and we know what the list of enabling technologies is,” he said.

There may also be some synergies between fission surface power and designs for nuclear propulsion, such as power conversion for nuclear electric propulsion systems. He recommended that designs for 40-kilowatt surface reactors be scalable to 100 kilowatts or more, enabling use in nuclear propulsion.

Despite the challenges, advocates of FSP see the technologies as essential for long-term lunar exploration because of the lunar night that lasts for two weeks. “You need something for the astronauts to do other than drive around on a rover for a couple weeks and then get back in the lander and go back home,” Bilardo said. “We want to go to stay this time.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...